Some things are best left aside. In the business of daily life, we have multiple memoranda (things to remember) and a full agenda (things to do), and so many people demanding our attention. And if you’re on a social network, some of those people might be real ignoramuses too, but somehow they still think they merit interaction; they may even provoke it. Somehow we need to need to do a triage. Never mind things to get around to. We need to make a list of things not to get around to. Things to ignore. And people to ignore.
So. A memorandum is a thing to remember; the word memorandum is a Latin singular neuter future passive participle of memoro ‘I bring to mind’; it means ‘to be remembered’, as in ‘a thing to be remembered’, i.e., ‘a thing to remember’. The plural is memoranda. Similarly, agenda is the neuter plural or feminine singular meaning ‘thing(s) to do’.
So what would be a thing to ignore?
That’s easy enough if you’re no ignoramus on Latin roots. The Latin verb ignoro means ‘I don’t know’ or ‘I don’t know about’ or ‘I ignore’. The first person plural conjugation is ignoramus ‘we don’t know; we ignore’. That word was pressed into service as the name of a lawyer in the 1615 play Ignoramus by Georges Ruggle, and from that has come to be the English noun we all know. (You can’t pluralize it as ignorami because it’s not a noun in Latin.) So if ignoro is the verb, the future passive participle will be ignorandus, ignoranda, ignorandum in masculine, feminine, and neuter, respectively. Since we normally use the neuter – memorandum, originally plural agenda – we can go with ignorandum for a single thing to ignore, and ignoranda for a list of things to ignore.
We can, if we really want to be exact, use the masculine for a single male who needs ignoring: ignorandus (plural ignorandi). This is most likely to be of use on social networking sites, where one may encounter randos – random dudes who just butt in and expect unearned attention to their obnoxious opinions. It works especially well because it is so close to ignoranus. Should that be ignoramus? No, it’s a popular wordplay: an ignoranus is a person who is both an ignoramus and an anus (you may more likely use the English equivalent for the latter). We may say with confidence that every ignoranus is an ignorandus to add to the ignoranda.
And, as an added bonus, the masculine accusative plural is ignorandos, which means that “Just ignore the ignorandos” is actually using proper Latin. The singular dative and ablative are ignorando, so “I want to get away from that ignorando” is also using proper Latin. (The whole declension is on Wiktionary.)